How much sun does Southern Ragweed need?

Southern Ragweed grows best in full sun conditions.

When does Southern Ragweed bloom?

Southern Ragweed blooms in July, August, and September.

Where is Southern Ragweed native?

Southern Ragweed (Ambrosia bidentata) is native to AL, AR, CT, GA and 20 more states, per the World Checklist of Vascular Plants (Kew).

What butterflies or moths does Southern Ragweed host?

Southern Ragweed is a larval host plant for red-banded hairstreak.

Is Southern Ragweed HOA-friendly?

Southern Ragweed takes more care to look intentional in a front yard. Consider it for backyard or mid-zone beds rather than the street edge.

Southern Ragweed

Name: Pollinator Patch
Author: Pollinator Patch

Ambrosia bidentata

Last reviewed: August 2026

Toxicity unknown

Southern Ragweed (Ambrosia bidentata) is not listed by the ASPCA Animal Poison Control Center (opens in new tab) or the other sources we check, so we have no verdict for it either way. Absence from those lists is not a clearance. If your pet shows symptoms after eating any plant, call the ASPCA at (888) 426-4435.

Light

full sun

Water

low

Size

12"–48" H × 6"–24" W

Bloom

Jul, Aug, Sep

Native to

AL, AR, CT, GA and 20 more states

Pollinators

bees, beetles, flies

Before you buy

Your city may pay you to plant this

Cities and water utilities offer rebates for replacing lawn with native and water-wise plants. We track 452 programs across 44 states, each with a link to the provider and the date we last checked it.

Find rebates in your area

Browse plants for this ecoregion

Cross Timbers South Central Plains Eastern Temperate Forests Ozark Highlands Central Irregular Plains Piedmont Southeastern Plains Ridge and Valley Interior Plateau Interior River Valleys and Hills Mississippi Alluvial Plain Mississippi Valley Loess Plains

Southern ragweed is an annual wildflower that grows 1-4 feet tall with small, inconspicuous greenish flowers from summer through early fall. This native plant thrives in full sun and drought conditions, making it well-suited to low-maintenance naturalized areas. It produces abundant pollen and seeds that support wildlife through the growing season.

In an HOA neighborhood

Southern Ragweed takes more care to keep looking intentional in a front yard. Maintenance level: low. Consider it for backyard or mid-zone beds rather than the street edge.

Works well in: backyard only.

Widely considered a weed by homeowners
Produces allergenic pollen
Informal appearance conflicts with maintained landscape expectations

Wildlife value

Host plant for red-banded hairstreak.

The flowers attract bees, beetles, and flies during summer blooming. Seeds provide food for birds, particularly finches and sparrows in fall.

Common questions

How much sun does Southern Ragweed need?: Southern Ragweed grows best in full sun conditions.
When does Southern Ragweed bloom?: Southern Ragweed blooms in July, August, and September.
Where is Southern Ragweed native?: Southern Ragweed (Ambrosia bidentata) is native to AL, AR, CT, GA and 20 more states, per the World Checklist of Vascular Plants (Kew).
What butterflies or moths does Southern Ragweed host?: Southern Ragweed is a larval host plant for red-banded hairstreak.
Is Southern Ragweed HOA-friendly?: Southern Ragweed takes more care to look intentional in a front yard. Consider it for backyard or mid-zone beds rather than the street edge.

Native range data from the World Checklist of Vascular Plants (Kew). Pollinator and host plant associations compiled from GBIF, iNaturalist, and published ecological literature.

If something looks wrong

Common plant problems, and what to check first

These come up on almost any plant. Each guide lists the likely causes in the order they are worth ruling out, with one thing to check before you act on any of them, and links to the source it came from.

See all plant problem guides

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